The present invention relates, in general, to surgical fastening instrument that prevents the instrument from being fired when empty, more particularly, to a surgical fastening instrument for attaching a prosthetic over a hernia, the surgical instrument having a locking mechanism that prevents movement of an actuation trigger after the last fastener is placed.
Surgical fastening instruments carry a number of surgical fasteners which are typically placed to ligate a vessel, hemostatically staple and cut tissue or to attach a prosthetic to tissue. All of these instruments contain a plurality of fasteners, which can be placed in a single firing, or in multiple firings. Single firing instruments, such as endocutters or various stapling instruments, contain a plurality of fasteners that are placed within tissue in a single firing.
In the case of endocutters or surgical staplers, the plurality of staples are contained within the stapling instrument in a replaceable stapling cartridge that holds up to six row of fine wire staples. The instrument is placed into the body, an anvil is used to clamp tissue against the replaceable cartridge, and the instrument is fired. Firing places all of the fasteners into tissue, and advances a knife to cut the tissue between the innermost rows. Once the cartridge is fired, it is desirable to lock the trigger of the endocutter to indicate to the surgeon that the instrument is empty. A U.S. Pat. No. 5,878,938 by Bittner et al. discloses a surgical stapler locking mechanism or lockout that uses a leaf spring to automatically lift a knife of the cartridge after firing, locking the instrument from firing. U.S. Pat. No. 5,673,842, also by Bittner et al. teaches a locking mechanism using an elongated member that automatically rotates from a first position to a second position as the instrument is fired. With the locking arm in the second position, the knife is free to translate upwardly and to lock the instrument. The above mechanisms incorporate an automatic lockout mechanism that depends on the movement of a knife. Of interest are surgical fastening instruments that do not contain knives.
Another type of locking mechanism is used with a disposable knife-less linear stapler such as that described in U.S. Pat. No. 4,527,724 by Chow et al. The instrument taught by Chow et al. is a trigger safety that prevents closure of the trigger. The trigger safety is hingedly attached to a handgrip of the surgical instrument and is foldable to a locking position to contact and prevent movement of the actuation trigger. This locking mechanism differs from the previously described automatic locking mechanisms in that it requires manual engagement and disengagement of the locking mechanism.
The above mechanism indeed locks the trigger of a single firing surgical instrument that has no knife, and requires manual engagement of the lockout. However, the above instruments are not multifire instruments. Multifire instruments contain a plurality of fasteners that are held within the surgical instrument, and the fasteners can be applied one at a time. These instruments are capable of multiple firings or applications of fasteners to tissue. These types of instruments can be fired repeatedly until the instrument runs out of fasteners or the surgery is complete.
One well known multi-firing instrument is a clip applier such as the ER320 LIGACLIP(trademark) Multiple Clip Applier manufactured and sold by Ethicon EndoEND-Surgery, Cincinnati, Ohio. Clip appliers are used to close or ligate vessels during surgery, and are commonly used to ligate the cystic duct and cystic artery during the removal of a gall bladder. These surgical instruments can contain up to twenty clips and contain a yellow feed shoe that pushes or feeds the clips distally within the instrument. A lockout is operatively attached to the yellow feed shoe, and falls into an opening within the feed bar to lock the feed bar of the instrument when the last clip is fed. The locked feed bar prevents the feed mechanism, the trigger, and the clip forming mechanism from moving. A locking mechanism of this type is described in U.S. Pat. No. 5,171,249 by Stefanchik et al. Whereas this locking mechanism is automatic, and the instrument contains no knife, it depends on linear motion of elements of the mechanism to lock the trigger of the surgical instrument.
Of special interest are surgical fastening instruments that are used to attach prosthetics such as a hernia mesh to tissue. One type of these devices employs a lockout. The surgical instrument is a multi-firing coil fastening applier that uses helical wire fasteners. The helical wire fasteners are stored serially within the shaft, and are corkscrewed or rotated into tissue. A variation of this surgical instrument is a coil fastening applier and remover. The coil fastening applier and remover is unique in the realm of hernia mesh attachment instruments, as it is able to remove fasteners from tissue. A user activated lockout mechanism is provided that locks an internal drive rod. Next, the instrument is placed over and engaged with a coil fastener positioned within tissue. The coil fastener applier is rotated to withdraw the coil fastener from tissue. Unlocking the lockout reactivates the coil fastener applying mechanism. A locking mechanism of this type is found in PCT application No. WO 98/11814 by Holstein et al. Although there is a lockout upon this hernial fastening instrument, it is not automatically activated when the last fastener is fired. Rather, the lockout is used to disengage and engage the coil fastener applying mechanism and does not lock all of the functions of the instrument.
Yet another locking mechanism for a multi-firing fastening instrument is described in European Patent Specification EP 0 392 750 by Green et al. The locking mechanism is for a fascia stapler, and has a lockout to prevent firing of the stapler when it is empty. A ring shaped counter wheel is provided having a plurality of equal spaced tabs extending radially inwardly, and one cross bar across one pair of the tabs to create a closed hoop. The number of tabs corresponds to the number of staples within the stapler. A longitudinally translating lever having an angled forward end reciprocates within the instrument. The angled lever, when reciprocated distally, contacts the tabs and snaps upwardly to rotate the counter wheel. A trigger also moves distally with the angled lever and normally slips between two tabs of the counter wheel. When the last staple is fired, the cross bar of the hoop engages with the trigger pushing it proximally to release a bolt, which snaps through the trigger and locks the handle of the stapler. Whereas the above stapling instrument utilizes a rotary lockout mechanism, the lockout mechanism is both complicated and expensive. Additionally, it also uses a secondary mechanism to rotate the counter wheel, which adds further cost and complexity to the mechanism.
What is needed is an improved lockout mechanism for a surgical instrument that can attach a prosthetic to tissue. Such a mechanism would provide superior advantages such as lower cost, reduced complexity, and automatic operation. Presently, there are no known rotary lockout mechanisms for a surgical fastening instrument that can meet all of the needs outlined above
In accordance with the present invention there is provided a surgical fastening instrument. The instrument includes a handle and a shaft extending from the handle. The shaft contains a plurality of surgical fasteners therein. The instrument also has a mechanism for first distally deploying a penetrating member from the distal end of the shaft and thereafter feeding at least one of the surgical fasteners distally from the penetrating member. The instrument further includes a lockout mechanism for preventing the penetrating member from deploying from the shaft upon feeding all of the plurality of surgical fasteners from the shaft.